<form name = "comments" action="<?php $_SERVER['PHP_SELF'] ?>" method="post">
Ваше имя:<br>
<input type="text" name="cname" /><br>
Ваш комментарий:<br />
<textarea name="commarea" cols="50" rows="5"></textarea><br />
<br />
<input type="hidden" name="pid" value="<?=$comm?>" />
<input type="submit" name = "csubmit" value="Отправить" />
</form>